Project based on V-USB software and 4-key-keyboard code. For remote operation with Canon EOS camera. Sends “space” for Canon Utility software or “F8 – take a photo”, “F9 – take a preview photo” for use with DSLR Remote Pro. I was changing keys scan codes descriptions in program code and remove needless fourth key (named “switch 3” on source schematic). Firmware uploading can be done without HVSP programmer and without AVR ATtiny85‘s reset pin disabling. Prototype board was divided for two segments: USB voltage converter and uC + buttons section.